The invention relates to traps in low-pressure drain plumbing applications, in particular to readily cleanable traps which function as gas traps and those that capture heavy sediment and trash that flow into the trap itself. This particular design incorporates an overflow mechanism that allows the drain to keep flowing in the event that the trap portion of the drain becomes clogged and does so without violating the integrity of the gas trapping feature desired in drain traps.
Various styles of traps that prevent the escape of sewer gas through the drain have been available since the beginnings of indoor plumbing. The P and S style traps are those most commonly used over the last century. A trap that provides a removable cup is exhibited in U.S. Pat. Nos. 1,210,201 and 4,700,412. Other types of cleanable traps are shown in U.S. Pat. Nos. 2,742,101, 3,994,031, 2,170,390, and 919,701.